Hall effects on unsteady duct flow of a non-Newtonian fluid in a porous medium

The unsteady flow of an incompressible Oldroyd-B fluid in a circular duct embedded in a porous medium is studied. The fluid is conducting in the presence of a transverse magnetic field and the influence of Hall currents is investigated. The motion in the duct is generated by a given but arbitrary time dependent inlet volume flow rate. Laplace transform technique is used to determine the exact solutions for the four cases: (a) constantly accelerated flow, (b) sudden started flow, (c) the flow rate has a trapezoidal variation with time and (d) oscillatory flow.